osmocom
/
wireshark
14
0
Fork 1
Code Issues Pull Requests Projects Releases Wiki Activity

STUN: fix calculation of CRC-32 with TCP framing 

According to RFC 8489:
Sec 1: "All STUN messages start with a fixed header that includes a method,
a class, and the transaction ID".
Sec 14.7: "The value of the attribute is computed as the CRC-32 of the STUN
message up to (but excluding) the FINGERPRINT attribute itself".

Even if the RFCs are not cristal clear, it seems that the "TCP Stream
length" field (described in RFC 4571) should be excluded from the CRC-32
calculation.
This commit is contained in:
Nardi Ivan 2022-09-11 17:49:57 +02:00 committed by A Wireshark GitLab Utility
parent a48298a93a
commit 961bc71e53
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
epan/dissectors/packet-stun.c
View File

@ -1537,7 +1537,7 @@ dissect_stun_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboole
case FINGERPRINT:
if (att_length < 4)
break;
proto_tree_add_checksum(att_tree, tvb, offset, hf_stun_att_crc32, hf_stun_att_crc32_status, &ei_stun_fingerprint_bad, pinfo, crc32_ccitt_tvb(tvb, offset-4) ^ 0x5354554e, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
proto_tree_add_checksum(att_tree, tvb, offset, hf_stun_att_crc32, hf_stun_att_crc32_status, &ei_stun_fingerprint_bad, pinfo, crc32_ccitt_tvb_offset(tvb, tcp_framing_offset, offset-4-tcp_framing_offset) ^ 0x5354554e, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
break;
case ICE_CONTROLLED: